Predicting barotrauma susceptibility for downstream passage at river infrastructure (#96)

Water Research Laboratory, University of New South Wales, Manly Vale, Sydney, New South Wales, Australia

Fisheries , New South Wales Department of Industry, Taylors Beach, New South Wales, Australia

Institute of Land Water and Society, Charles Sturt University, Albury, New South Wales, Australia

When fish pass downstream through river infrastructure, such as dams and weirs, barotrauma mayoccur due to a rapid decrease in pressure. In severe cases, barotrauma may lead to mortality.Different species are likely to respond very different to these rapid decreases in pressure. Therefore,to predict barotrauma for a specific species, surrogate species may not be a valid approach, and itmay be necessary to examine each species individually. For this study, Australian bass and carpgudgeon were exposed to a range of rapid decompressions using hyper/hypobaric hydro-chambersand examined for injuries and mortality. Rapid decompression data from these two species, inaddition to previously examined Murray cod and silver perch were evaluated to determine whichinjuries were highly associated with and likely to predict mortality. Dose-response logisticregressions models were developed for each species to predict injury and mortality over a range ofrapid decompressions. These models are a valuable tool for estimating injury and mortality rates forfish passing though river infrastructure and can be applied to specific sites where pressure profileshave been developed. Applying these models to current and future infrastructure can provideimportant insight into what measures or design alterations may be necessary to directly reduce thenegative impacts of river infrastructure on fish populations.